Alkylthio alkyl avermectins are active antiparasitic agents

Abstract

Avermectin compounds are substituted at the 4", 4' or 13-postion hydroxy group with an alkylthioalkyl group and are optionally substituted at the other reactive positions of the avermectin molecule. The compounds are prepared by reacting protected avermectins, avermectin monosaccharides or avermectin aglycones with dialkylsulfoxides. The compounds are potent antiparasitic agents and compositions for such uses are also disclosed.

What is claimed is: 
     
       1. A compound having the formula ##STR4## where: n is 0; A is single or double bond;   R 1  is present only when A is a single bond and is H, OH, ═O, ═NOCH 3  or halogen;   R 2  is C 1  -C 6  alkyl, C 2  -C 6  alkenyl, C 3  -C 8  cycloalkyl, C 4  -C 8  cycloalkenyl, phenyl, furyl or thienyl;   R 3  is OH or ═NOH;   B is a single or double bond;   R 5  is present only when B is a single bond and is H, OH or halogen;   R 4  is ##STR5##  and R 6  is hydrogen or C 1  -C 3  alkyl.   
     
     
       2. A compound of claim 1 where A is a single bond;   R 1  is H, OH or ═O;   R 2  is C 1  -C 6  alkyl or C 3  -C 8  cycloalkyl;   R 3  is OH;   B is a double bond; and   R 6  is hydrogen or methyl.   
     
     
       3. A compound of claim 2 where A is a single bond;   R 1  is H or OH;   R 2  is C 3  -C 4  alkyl or C 5  -C 6  cycloalkyl;   R 3  is OH;   B is a double bond; and   R 6  is hydrogen.   
     
     
       4. A compound of claim 1 which is selected from the group consisting of 13-O-Methylthiomethyl-22,23-dihydroavermectin B1 aglycone;   13-Epi-O-methylthiomethyl-22,23-dihydroavermectin B1 aglycone;   13-O-Methylthiomethyl avermectin B1 aglycone;   13-O-Methylthiomethyl-10,11,22,23-tetrahydroavermectin B1 agylcone;   13-O-Methylthiomethyl-10-hydroxy-10,11,22,23-tetrahydroavermectin B1 aglycone; and   13-O-Methylthiomethyl-10-fluoro-10,11,22,23-tetrahydro avermectin B1 aglycone.   
     
     
       5. A method for the treatment of parasitic infections in animals which comprise administering to such animals infected with parasites an effective amount of a compound of claim 1. 
     
     
       6. A method for the treatment of parasitic infections of plants, soil or premises which comprise applying to such plants, soil or premises infected with parasites an effective amount of a compound of claim 1. 
     
     
       7. A composition useful for the treatment of parasitic infections of animals or parasitic infestations of plants, soil or premises which comprise an inert carrier and an effective amount of a compound of claim 1.